View the original community article here
Last tested: Feb 20, 2021
When we run a query in sql runner in Looker, there is a network request in which we are sending that query to your database, and the network request will be active for as long as it takes the query to finish. Essentially, a socket is maintained between the client browser and the looker server. If this socket is closed (by a user closing the tab, or a VPN killing it) then Looker will send a kill request to the database and kill the query on the db side too - which is then when the query shows up as "Canceled" in the Queries panel.